Your HVAC drain is possibly pluged.
The drain is located on the firewall,
toward the bottom - right of center.
Heres a pic of the drain tubs(it an elbow that points downward)
http://i28.photobucket.com/albums/c2.../HVACDrain.jpg
You can use a stiff wire to clear it or some compressed air.
Btw- A coat hanger may be to stiff.